The cyclodienes chlordane and heptachlor were generally regarded as the most effective termiticides in history. They provided 100% control of subterranean termites for 20-30 years or more.
Although chlorinated hydrocarbons had been described since 1873, their insecticidal properties were not discovered until 1939 when Paul Muller, who later received a Nobel prize for doing so, demonstrated the efficacy of DDT. During World War II DDT was credited with saving literally thousands of lives. Later its effectiveness in the field of disease vector control led many to mistakenly believe that it might end the scourge of malaria forever. Not surprisingly, DDT and the related chlorinated hydrocarbons dieldrin, aldrin, chlordane and heptachlor were tested and used extensively as termiticides. For their part, chlordane and heptachlor proved extremely effective against subterranean termites, particularly because even at low rates of application they remained effective in the soil long after the soil was treated.
The extraordinary persistence of the cyclodienes, which helped make them famous as termiticides and as agricultural pesticides, also led to their downfall. It was shown that they accumulated in the food chain, where processes such as biomagnification increased the risk of injury to non-target organisms, including humans.
After the EPA was established in 1970 data began to surface showing noticeable residues of oxychlordane in human fat tissue. Because of these concerns the use of cyclodienes on food crops in the U.S. was banned. Later, despite intense lobbying by the pest control industry, they were further banned from the field of termite control, effective in the month of April, 1987. Other countries followed suit until, today, neither chlordane nor heptachlor may be legally applied anywhere in the world.
This action, while warranted, left a significant void. No equivalent soil drench termiticides have since been discovered to replace the cyclodienes.
In the early 1980's, as it appeared that the days of the cyclodienes as termiticides were numbered, several alternative chemicals were registered with the EPA. Since that time, the number of such alternative products has risen sharply. Reports surfacing not long after the 1987 ban indicated that many of these not only worked as well, but were even more effective than the cyclodienes. However, the new products only lasted in the soil for a few years. Furthermore, their longevity was affected by type, pH, and organic content of the soil. Even under favorable conditions, a significant depletion of termiticide occurred by the end of the fifth year following application.
Homeowners and businesses in the United States of America annually spend in excess of $1.7 billion to combat termite infestations. Therefore a sizeable market for effective termite extermination products and methods exists in this country. Significant expenditures also occur on the European continent, in Asia, and in Australia. Termite damage to wooden structures is a phenomenon that spans the globe. The need for effective termite control exists throughout much of the populated world. Recent Termite Control Developments
Approximately 160 patents relating to termite control were issued by the U.S. Patent Office between 1971 and the end of 1998. Some 108 of these, representing 68% of the total, were filed after the cyclodienes were banned in 1987.
Almost 39% of the termite-related patents issued over the past 26 years involved new termite toxicants. Many of these are used in the same manner as the cyclodienes, i.e., as soil drenches, serving as repellents and barriers against termite infestation. Others are intended to suppress a termite colony's population by poisoning or otherwise rendering ineffective a large number of its members. In this latter group are found contact poisons, biological agents, e.g. Metarrhizium anisopliae, gastrointestinal poisons, e.g., Sulfluramid, and insect growth regulators and chitin synthesis inhibitors, e.g., Hexaflumuron.
A number of physical barriers have also been invented during this period. For example, U.S. Pat. No. 5,417,017 discloses a stainless steel mesh that is woven so tightly that termites are unable to pass through it.
Besides new toxicants and physical barriers, new methodologies for creating safer, more effective methods of applying chemically based termite barriers have been invented as well. Some of these seek to reduce the risk of human exposure to chemicals:
U.S. Pat. No. 5,465,525 issued Nov. 14, 1995 teaches utilizing a computer-controlled robot having an array of sensors, video linkages and pesticide dispensers. Human operators are located remotely where, safe from chemical exposure, they are able to identify where and how extensively termiticides should be dispensed by the robot beneath architectural structures.
U.S. Pat. No. 5,346,699 issued Sep. 13, 1994 teaches using a wet foaming agent to allow a relatively small amount of termite toxicant to create a termite barrier in a void. The foam is used to fill voids in walls and under concrete foundations and walkways, wetting all surfaces of the void before collapsing. Consequently, termites passing over any surface of the void will receive a dose of the toxicant.
U.S. Pat. No. 5,317,831 issued Jun. 7, 1994 teaches using a permanently installed system of tubes and nozzles to periodically deliver measured amounts of liquid termite control fluids throughout the hard-to-reach sub-floor region of structures with pier and beam foundations. Similarly, U.S. Pat. No. 5,819,466 issued Oct. 13, 1998 describes a system that performs an analogous service around the perimeters of homes with monolithic concrete foundations.
New approaches have also been developed in the fields of termite detection, monitoring and baiting. When termite colonies are detected early in their development the door is open to suppress them before they can cause any significant damage.
Detection, monitoring and baiting methods focus on pinpointing active termites and feeding them small, measured amounts of termite-specific toxicants. These are contained in tamper resistant bait servers, and act to reduce the population of the termite colony to the point where it cannot infest entities of economic value.
The process of reducing the population of the termite colony to the point where it cannot infest entities of economic value is referred to in the literature as suppression and/or elimination. However, subterranean termites are cryptic organisms whose activities are generally hidden from view, and this makes it difficult or impossible to know for certain that colony elimination has taken place. Furthermore, while subterranean termite biology is still in its infancy, what is already known about these creatures suggests that the termite colony is often capable of surviving even under extremely unfavorable conditions. Together, these facts commend more humble expectations from a given treatment regime than are implied by the term "elimination". For this reason this process will be referred to in this document as suppression.
Once the termites in a specified area have been successfully suppressed, the area is monitored indefinitely for new signs of active termites. If new signs of active termites are found, a new round of toxicant baiting is initiated.
Termite detection and baiting has been investigated and tested to some degree since before the turn of the century. Scientific interest in this method began to increase in the late 1960's, and continued at.a low level in the 1970's and early 1980's. However, the skill and experience required to properly implement detection and baiting methodologies discouraged widespread exploration for technically or economically feasible approaches as long as the highly successful and inexpensive cyclodienes could be used. Following the 1987 ban a number of important advances in each of these fields has occurred in quick succession:
An acoustic emission detector, capable of sensing the vibrations produced by termites when they break the cellulose and lignin fibers of the wood they are consuming, is described in U.S. Pat. No. 4,895,025 issued Jun. 26, 1990. Since that date at least five other acoustic or vibration sensing devices have also been patented. An apparatus to be used to detect and bait termites is described in U.S. Pat. No. 5,695,776, issued Dec. 9, 1997. This apparatus includes both above-ground and in-ground devices. One of the in-ground devices, shown in the patent as FIG. 5, has been marketed for some time by the FMC.RTM. Corporation as the detector component of the FIRSTLINE.TM. Termite Bait Station. This detector component contains a non-toxic section of wood having the general features described in the patent, but without the toxin. It is typically inserted into the ground, with the top of the tube visible or, alternatively, with the entire unit buried underground.
The detector component must be inspected periodically by either withdrawing it from the ground, if its top is visible, or digging it up and then visually examining the wooden insert through the transparent plastic tubular enclosure for evidence of termites. If termites are noted by the inspector, a second component, this time containing a length of rolled single-faced corrugated cardboard impregnated with the toxicant 0.01% N-Ethyl perfluorooctanesulfonamide, commonly known as sulfluramid, is inserted into the soil near where the detector had been.
This in-ground version of the FIRSTLINE.TM. Termite Bait Station is interesting in that it apparently departs from the recent trend of using multifunctional devices serving as both detectors and bait servers. However, as the patent document discloses, the detector component was envisioned originally as a combination detector/server. Furthermore, personal communications with purchasers has revealed that the detector component, which is sold in a package with the toxicant-containing units, is often discarded unused because the diminutive size of the detector unit makes it difficult to find after it has been installed.
The same difficulty noted above pertains to the toxicant-containing, unit as well. Consequently, the above-ground version of the FIRSTLINE.TM. Termite Bait Station has generally been more popular than the in-ground version with pest control operators. As a result, while the FIRSTLINE.TM. Termite Bait Station is being used successfully to combat active termite infestations, it does not appear to have become widely accepted as part of a termite detection/prevention program, at least in the format recommended by the manufacturer.
Personal communications with pest control operators who have used the in-ground version of the FIRSTLINE.TM. Termite Bait Station have confirmed that some of them use alternative termite detectors with this product. For example, several pest control operators have stated that they use the TERMATROL.TM. termite detectors manufactured by Sector Diagnostics LLC with the FIRSTLINE.TM. Termite Bait Station. The TERMATROL.TM. termite detector is described in the U.S. Design Pat. No. 399,765, issued Oct. 20, 1998.
Another stand-alone termite detector, the PERIMETER PATROL SYSTEM.TM. detector, manufactured by the B&G Equipment Company, could also be used with the FIRSTLINE.TM. Termite Bait Station. Both TERMATROL.TM. and PERIMETER PATROL SYSTEM.TM. devices employ quasi-subterranean enclosures with tamper-resistant caps requiring special keys to gain access to the enclosure interior. Instructions with both of these systems suggest that, when termites have been found inside them, termite baits like FIRSTLINE.TM. or TERMINATE.TM. may subsequently be inserted directly into the detector enclosure. It is likely that some pest control operators are using these detectors in this manner, which would convert the detector unit into a detector/server, comparable in many respects to the other termite detector/servers presently on the market.
In January, 1999, the FMC Corporation began advertising SMARTDISK.TM., which is a modified in-ground detector/server. This device is larger than the in-ground device described above, and utilizes a grooved wooden food material impregnated with a toxin, encased in a cylindrical plastic tube. The dorsal surface of the plastic tube, which is transparent, is placed in the center of a disk 18 cm in diameter. The disk, as shown in the advertisement, is of a purple color, which would contrast with soil or grass and thus make the placement easier for an inspector to locate. Because the dorsal cap of the plastic tube is transparent, an inspector could presumably recognize termites crawling on the surface of the food material. However, moisture, other organisms, debris, soil and other contaminants would quickly obscure the interior surfaces of the tube and prevent visualization of the interior contents.
In any case, the SMARTDISK.TM. detector/server is intended to contain a toxicant impregnated food material when it is installed, which rules out using it as a detector alone.
While the FIRSTLINE.TM. and SMARTDISK.TM. Termite Bait Stations are marketed to pest control operators alone, The Spectrum Group is currently marketing a termite bait server directly to home owners under the trademark SPECTRACIDE TERMINATE.TM.. This bait server appears, outwardly, to be identical to the in-ground version of the toxicant-containing FIRSTLINE.TM. Termite Bait Station described above. Not only are the packaging and interior contents of these two products practically identical, but they both use the same percentage of the same active ingredient (0.01% sulfluramid). They are distinguished by the coloration of their plastic enclosures, however.
The SPECTRACIDE TERMINATE.TM. bait server is not provided with a detector component by the manufacturer, and instructions supplied by The Spectrum Group suggest that the SPECTRACIDE TERMINATE.TM. bait server should be inserted into the soil around the perimeter of a residential dwelling primarily to prevent termites from attacking the building. The bait server is supposed to be dug up periodically to determine if termites have consumed its contents, but the same difficulties noted with the FIRSTLINE.TM. Termite Bait Station make such an inspection difficult to perform. In any case, according to the manufacturer, the SPECTRACIDE TERMINATE.TM. bait servers are supposed to be replaced every nine months.
The recommended application of the SPECTRACIDE TERMINATE.TM. bait server suggests that the manufacturer envisions it as a purely prophylactic device. Without a detector, however, it is questionable whether this product represents a very cost-effective approach to termite prevention.
A system for detecting, monitoring and baiting termites is described in U.S. Pat. No. 5,676,960 issued Oct. 14, 1997 and U.S. Pat. No. 5,509,879 issued Mar. 11, 1997. These systems use a comprehensive termite detection, trapping, separation and treatment methodology to aggregate large numbers of the members of a termite colony. The termites are then manually coated with a termite toxicant mixed with an adhesive resin and released. Once the coated termites return to the colony the untreated workers instinctively groom them to remove the toxicant coating. In the process, the previously untreated workers contaminate themselves and their nest mates with lethal doses of the toxicant material.
The primary termite traps used in this invention consist of sections of plastic pipe containing rolls of corrugated cardboard and, alternatively, an added block of wood to provide a reserve supply of food. These primary traps are connected to one another and to an aggregating trap by lengths of cardboard tubing which is presumably placed underground. The aggregating trap is physically separate from the primary traps and is designed to contain considerably greater food mass and surface area for feeding than the primary traps. This allows a much larger number of termites to be contained in the aggregating trap than is possible in the primary traps.
This system, which is not known to have been placed on the market, is interesting because the bait service is performed manually. Obviously, this imposes a significant labor cost, especially considering the highly specialized and technically rigorous tasks involved.
Another termite detection, monitoring and baiting system is described in U.S. Pat. No. 5,329,726 issued Sep. 8, 1992. The apparatus described in this patent involves an in-ground termite detector/server combination containing a detector cartridge that is initially non-toxic. When termites begin feeding on the contents of this cartridge they and the physical damage they cause are noticeable to an inspector, but only after the cartridge has been physically withdrawn from the detector/server housing. Once termites are detected, the detector is converted to a pesticide-containing bait server by discarding the non-toxic feeder cartridge and replacing it with one containing a pesticide. Modifications to the in-ground apparatus that provide for above-ground termite detection and control are also described.
A later patent granted to the same inventors, U.S. Pat. No. 5,555,672 issued Sep. 17, 1996, describes the previously disclosed in-ground termite detector/server, a number of alternative embodiments that enable it to be used in above-ground applications, and guides for directing termite travel. These guides do not recruit termites to the detector/server, but make it difficult for them to leave once they arrive. A still later patent granted to the same inventors, U.S. Pat. No. 5,573,760 issued Nov. 12, 1996 again describes the originally disclosed in-ground termite detector/server alone.
Although the detector/server combination disclosed in these patents is not known to be marketed at the present time, many of the in-ground termite detector/servers placed on the market in the United States over the past four years share important elements and characteristics with it. For example, as already noted, most of these detector/servers are, for practical purposes, multifunctional devices.
The SENTRICON.RTM. Termite Colony Elimination System, marketed by DOW AgriSciences LLC, utilizes both above-ground and in-ground bait servers. The in-ground device used with this system is actually a detector/server combination, while the above-ground devices may be properly described as server/monitors. The in-ground detector/server consists of a subterranean plastic housing containing, initially, two approximately 27 g strips of wood resting on a plastic disk attached to a thin plastic shaft. This shaft extends from the bottom disk to the top of the subterranean housing, and an ergonomic grip is provided at the top so that an inspector may, by pulling up on the shaft, lift the wood strips out of the plastic housing for examination. The top of the plastic housing is covered by a plastic cap that requires a special key both to cap and to uncap the device. A unique UPC bar code strip, concealed under the cap and accessible only after the cap has been removed and inverted, identifies each specific SENTRICON.RTM. station.
Inspection of an in-ground SENTRICON.RTM. station of the design described above requires the inspector to perform ten specific steps in a repetitive fashion for each station inspected. These are:
(1) locate the SENTRICON.RTM. station, PA1 (2) kneel, squat, or bend over the station, PA1 (3) remove the station's cap with a special key, PA1 (4) swipe the barcode reader of the hand held computer required to be used with the SENTRICON.RTM. station over the station's unique barcode, PA1 (5) grip the wood strip cradle shaft and lift the wood strips out of the station, PA1 (6) carefully examine the wood strips for evidence of termite activity, PA1 (7) on finding no signs of termite activity replace the wood strips into the station, or on finding signs of termites place a toxicant-containing tube into the station in place of the wood strips, PA1 (8) code the status of the station into the hand-held computer, PA1 (9) use the special key to replace the cap on the station, and PA1 (10) return to an upright position to resume the inspection process.
Personal communications with pest control operators who are currently working with this system suggest that an experienced, highly motivated inspector will be able to complete all of these steps, consistently, in the span of two minutes. An inexperienced, or less motivated inspector may take considerably longer. Thus, the time required to perform an inspection of a series of installed SENTRICON.RTM. stations can be expected to be on the order of two minutes per station, and possibly two or three times that long. This loading severely limits the number of stations that can be placed at a given site. Consequently, SENTRICON.RTM. stations are typically placed at intervals of one station for every 3-9 meters, or 10-30 ft., of monitored perimeter, and the installation is generally limited to the perimeter of the primary structure at the site.
Pest control operators who use the SENTRICON.RTM. system indicate that, even with active termite infestations at the installation site, a considerable lapse time lapse may occur between the date of installation and the discovery of active termites in one or more of the installed detector/servers. This is not surprising, especially in light of reports from researchers showing that it is commonplace for only 7% of the termite detectors of various designs to ever have active termites found in them.
The EXTERRA.TM. termite control system was placed on the market in early 1998 by ENSYSTEX Incorporated. This system is similar to the SENTRICON.RTM. system, in that its in-ground detector/server is a dual-function device. Inspection of this system is slightly less complicated, potentially consisting of only 8 steps since the use of a hand-held computer is optional. However, a computerized tracking system is marketed with this system and the manufacturer encourages its use. Furthermore, the time required to perform an inspection, even without the computerized tracking system, may not be reduced by much.
The wooden strips used as termite attracting elements in this device are fixed to the interior sides of the station and cannot be removed. This requires that the inspector crouch down and peer directly into the interior of the station to perform an inspection. The sides of the wood strips closest to the surrounding soil, and hence the sides most likely to be attacked first by the termites, are turned to the outside and thus never visible to the inspector. This may cause a considerable time lapse to occur between the initiation of a termite infestation and its discovery. In any case, the inspector is required to perform near-acrobatic maneuvers to properly examine the wooden strips in the detector, and this may adversely impact the effectiveness as well as the speed of the inspection process.
Not surprisingly, the detector/servers of the EXTERRA.TM. termite control system are suggested by the manufacturer to be placed up to 6 meters apart.
Another device known as a TERMINIX TERMONETER comprises a wooden stake, measuring approximately 2.5.times.5.times.30 cm, with a pointed ventral end and a blunt dorsal end. Presumably, these stakes are intended to be inspected periodically by pulling them out of the ground, visually examining them for signs of termite activity, and replacing them into the hole they were withdrawn from. There are several known problems with this particular technique. For example, placing the stakes more than 15 cm from the perimeter of the structure, and at such lengthy intervals, is known to significantly increase the time required for termites to find them.
Furthermore, it is not possible to perform regular lawn maintenance with the stakes in place, which generally means they will be pulled up or chopped up the next time the lawn is mowed, and few gardeners are gracious enough to replace the stakes where they had been. If termites are ever discovered in the stakes, the trauma caused by withdrawing the stake and replacing it into the hole, whether this is done by the inspector or by a gardener, may cause the termites to abandon that location for some time. Thus, finding termites in that location does not mean that the location yet remains a good place to install a toxicant bait.
Factors Affecting Cost
The new approaches to termite control that have followed the ban on cyclodiene termiticides are significantly more costly to the consumer than the pre-1987 approaches they replace. As a result, homeowners find it increasingly difficult to afford many of the newer treatment methods. Many medical institutions, municipalities and public school systems, whose plant maintenance budgets are already stretched thin, find themselves in the same spot.
The sharp increase in cost for the new termite treatment approaches has a number of causes; some unique to the approach involved. But one major cause common to all of them involves labor. Each requires the services of highly skilled and experienced technicians. Each also requires more of the technician's time than before. This is especially the case for termite detection and baiting methodologies.
Another major cost booster common to all of the termite detection and baiting systems involves the generally cryptic nature of their convertible detector/servers. Of particular interest is the fact that the inspection of these termite detector/servers requires, as a prerequisite, the completion of several non-trivial, time-consuming and physically challenging tasks.
For example, it is necessary to first dig some of these detector/servers out of the ground e.g., U.S. Pat. No. 5,695,776. In other cases a cap must first be removed before extracting an interior bait cartridge e.g., U.S. Pat. No. 5,573,760. In yet another case the interior bait is left undisturbed but a cap must first be removed to expose the interior termite food source e.g., W09726788A1. All of the caps involved, except that of U.S. Pat. No. 5,573,760, which is not known to be presently on the market, stipulate the use of special keys to prevent unauthorized access to the interior of the detector/server.
Once the interiors of these detector/servers are exposed, the inspector must still visually examine them for evidence of active termites. This process is often complicated by extraneous factors such as the presence of other organisms and debris.
Human Factors
It is generally possible to establish, from an analysis of the various steps involved in a given task, how well a single iteration of that task is likely to be performed by an average worker. It is more difficult to establish how well such a task is likely to be performed repetitively because, aside from the complexity of the task itself, repetition introduces other variables that must also be accounted for.
It is well known in the field of human factors engineering that the performance of complex, repetitive operations varies both qualitatively and quantitatively as a function of the nature of the psychological and physiological rewards and detractors associated with them. For example, positive psychological rewards have a motivating influence and consistently lead to improvements in performance. Conversely, negative psychological detractors, or physiological detractors inherent to complex, repetitive task schemata, or those that typically cause the operator to experience pain and discomfort when the operation is performed, have a demotivating influence and consistently lead to performance degradation.
In the case of the inspection of termite detector/servers that are currently on the market, the inspector receives a positive psychological reward when a previously quiescent detector is discovered to contain active termites. The positive reward presumably derives from the fact that the inspection process has successfully revealed important, new information. This reinforces its worth and that of the inspector as well.
On the other hand, discovering a presently quiescent detector/server that had been quiescent on all previous inspections is mildly disappointing the first time, but develops into an increasingly severe psychological detraction with the number of consecutively quiescent detector/servers inspected. These effects are of little or no consequence for trivial tasks or for tasks that are performed infrequently, but they increase in significance with the mental and physical complexity of the task and its frequency of repetition. The inspection of the detector/server may be perceived as a waste of the inspector's time since it only reinforces negative data. This lowers the worth of the inspection process, and by inference, that of the inspector as well.
Numerous studies have been published describing the results of field trials using one or more of the currently marketed detector/servers. Typically, these papers have shown that, even in areas known to harbor active subterranean termite infestations, it is not unusual for only a small fraction of the deployed detector/servers to become infested with active termites. Obviously, for areas devoid of active termites, where the detector/servers serve as early warning devices, none of the detector/servers will become infested until termite foragers encroach on the area, a process that may not develop for years. Despite this, it is critically important that each detector/server be inspected carefully and completely on the chance that active termites will be found. The risk of performance degradation, under such conditions, is very great.
In addition to the psychological detractors common to the currently marketed termite detector/servers, they are also plagued with a number of physiological detractors. The inspection of each termite detector requires the articulation of all the major joints in the upper and lower extremities as well as flexion of the cervical, thoracic and lumbar spine. These articulations are, for example, a necessary part of wielding a shovel to dig up a detector/server and of bending over or squatting down to pick it up for inspection. For capped detector/servers, the inspector either bends over, squats down or kneels, removes the cap, and either withdraws the contents or crouches closer to the detector/server before conducting a visual examination.
These physically challenging articulations suggest that an individual with a perfectly healthy musculature and spine, and with no diseases of the joints, may naturally experience some degree of mild pain and discomfort during the inspection of a single detector/server. Individuals with orthopedic dysfunctions will experience even greater degrees of pain and discomfort, depending on the location and severity of their disease. Such persons will have considerable difficulty performing these steps consistently well, if they can perform them at all.
According to the Arthritis Foundation, nearly 1 in 7 Americans is afflicted with arthritis, making this disease one of the most prevalent chronic health problems and the number one cause of limitation in movement in the United States. Furthermore, anyone can get arthritis. It affects people in all age groups. A recent study indicates that the prevalence of arthritis or other rheumatic condition within the U.S. is expected to climb to 59.4 million, or 18.2% of the population by the year 2020. It should be clear, therefore, that complex tasks, especially those involving repetition, should be designed to minimize the incidence of pain and discomfort for those operators who may be afflicted with arthritis or related disorders.
Mild arthritis will not prevent an inspector from performing infrequent inspections of one or two of any of the detector/servers now on the market. Unfortunately, they are not designed to be inspected infrequently, nor one or two at a time. A successful termite technician can be expected to spend several hours a day inspecting for termite activity at various client locations. Under such conditions, with the orthopedic manipulations required to inspect these devices, even the mildest form of arthritis might become a debilitating handicap within a short period.
These orthopedic manipulations also occur prior to the most critical part of the inspection process, namely the visual examination of the bait material for evidence of active termites. With the detector/servers currently on the market, the inspector is required to assume the role of a skilled field entomologist, marshalling a depth of knowledge, experience and an educated eye to visually scan for evidence of termite activity.
Inspecting the interior of an open, subterranean but non-removable bait station for the presence of termites from a crouching position, as required by one style of detector/server, or a removable detection stake or cartridge from other styles of detector/servers, requires excellent lighting and good visual acuity. If the inspector is visually impaired, or if light conditions are unfavorable, a satisfactory inspection is impossible without supplementary lighting, corrective eyewear and/or the use of magnification aids. During periods of high exterior temperatures and/or humidity, the use of corrective eyewear or magnification aids becomes more problematic, increasing the risk of poor performance on the part of the inspector.
The net of these considerations is that, owing to certain common design features, these termite detector/servers are encumbered by a number of significant negative physiological detractors that will be noted by all users. For those with even minor disabilities, i.e., for a sizeable fraction of the available work force, the user-unfriendly character of these devices will likely be so serious that quality of service must be sacrificed at once in order to avoid an unbearable level of discomfort and pain.
As in the case of the psychological detractors previously discussed, these negatives should be expected to result in serious performance degradations. Degradations in performance normally expected from both sets of causes would, for example, include reporting skipped stations as though they were actually inspected, and reporting incomplete, cursory inspections as though thorough inspections had been done.
Strong circumstantial evidence exists that the manufacturers of these devices are aware that inspections of their detector/servers may be prone to performance degradation. This evidence rests chiefly on the steps these manufacturers have been observed to take to limit the difficulties associated with the inspection process and mitigate the risks of skipped or incomplete inspections.
For example, hand-held computers equipped with scanning devices are often promoted as labor saving aids to the manual inspection process. There is no question that computers may help in the inspection and reporting process. However, in some cases the roles assigned to the computers make them little more than compliance enforcement tools designed to effectively prevent the false reporting of skipped stations. Their use in this role may impose an additional workload on the inspector, rather than the reduction in workload that the effectual implementation of computer-related aids should be expected to provide.
Ironically, far from mitigating over all risk, reliance on computer-related accessories as a means of forcing rule compliance may ultimately have the opposite effect. Even the most ingenious compliance enforcement programs are subject to manipulation and circumvention in the hands of clever and disenchanted operators. Furthermore, such measures, used alone, fail to guarantee that the inspector will perform the remaining steps of inspection in a competent and thorough fashion.
In another approach taken to limit the difficulties associated with inspecting existing in-ground termite detector/servers, the recommended interval between each termite detection unit is lengthened, so that fewer detector/servers are prescribed for a given site. Applicant's field testing has consistently shown that the maximum interval between detectors should be near 1.5 meters. The termite detector/servers on the market today, however, generally recommend an interval on the order of from 3 to 10 meters or more.
Although ignoring the difficulties involved in inspecting each individual detector/server, lengthening the recommended interval between them reduces the total of such difficulties that will be encountered at a given site. Unfortunately, the sensitivity of the detector/server installation suffers greatly in the process. It is important to include the perimeters of privacy fences, detached sheds, and such things as woodpiles in the detection zone, since many termite infestations begin at these locations. The emphasis on placing as few detector/servers as possible, however, generally rules these areas out in favor of a zone around the most important structure at the site.
Another approach has been to de-emphasize the use of in-ground detectors in favor of above-ground devices such as that disclosed in U.S. Pat. No. 5,832,658 issued Nov. 10, 1998. Above-ground termite monitors for subterranean termites are also discussed in a number of recent scientific studies. Often the above-ground devices are described as "monitors" that are deployed in much the same way, and for the same purpose, as termite detectors. There is no question that above-ground bait server devices may have an important place in certain subterranean termite treatment programs. However, encouraging the use of above-ground termite monitors and bait servers as the primary detectors of subterranean termites at a given site, and simultaneously de-emphasizing the use of in-ground subterranean termite detectors, is a questionable practice. The success of above-ground subterranean termite detectors means that termites are already infesting the entity being monitored, and the important early warning potential of an extensive in-ground termite detection system has been sacrificed.
U.S. Pat. No. 5,815,090 issued Sep. 29, 1998 proposes yet another approach to resolving the difficulties involved in manually inspecting the currently marketed in-ground termite detector/servers. The system disclosed in that patent takes the human inspector out of the picture altogether, in favor of a fully computerized termite sensing and reporting system. Computer-inspected termite sensors, comprised of termite edible material and an electrical conductor, are inserted into the soil to form a termite detection zone much the way the manually inspected detector/servers are.
The electrical conductor of the computer-inspected termite sensor is arranged in the form of a bridging circuit that is disrupted when termites feed on it. The sensor is attached to a computer whose software is capable of interpreting the electrical signals from the sensor and registering the presence of termites. Once such a system is installed at a site, its computer could be programmed to automatically dial a remote office to report the presence of termites, including their precise location within the site.
With this system the high costs associated with manual inspections of in-ground detector/servers are exchanged for the high costs of sophisticated computer-monitored termite sensors and their associated electronic accessories. Considering the severity of the difficulties associated with the inspection of the in-ground detector/servers now on the market, and assuming that these difficulties cannot be remedied within the framework of a manual inspection program, this invention would appear to offer a viable and reasonable alternative. At least it addresses the rewards/detractors issue, and conceivably improves the accuracy of the inspection process.
Rather than improving on existing manual inspection approaches, the inventor of U.S. Pat. No. 5,815,090 concluded that a computerized system, without human inspectors, stands a greater chance of success. In the summary provided with that patent the inventor noted that the reduced or eliminated need for manual inspections may allow for more comprehensive monitoring.
In other words, more computer-monitored sensors may be installed at a given site than would be practical for an installation of manually inspected detector/servers. This is a reasonable expectation if manually inspected termite detectors are inherently inefficient and this inefficiency is fundamentally linked to the need for human inspectors. In such a case, the inefficiency of manually inspected termite detector/servers is not susceptible to remediation.
A review of the relevant scientific literature published over the past 20 years has failed to find even one paper that addresses the physiological detractors of the human inspector/termite detector interface. Similarly, none of the termite-related patents issued by the U.S. Patent Office since 1971 appears to seek ways to make that interface more efficient. Instead, these studies and inventions either ignore the problem, make it worse by adding to the human inspector's workload, or propose new interfaces that eliminate human inspectors.
It is not obvious that remedial measures to date, capable of eliminating most or all of these physiological detractors, are available. Otherwise, these scientists and inventors would have discovered such measures, reported on them, and exploited their potential.
It is desired to provide an improved termite monitoring and detection apparatus that takes into account physiological detractors, provides an early indication of the presence of termites, and provides an effective suppression of termites.